Gravitation meter for measuring the vertical gradient of the gravity of the earth



Dec. 13, 1927. 1,652,255

W. SCHWEYDAR GRAVITA'IION METER FOR MEASURING THE VERTICAL GRADIENT OFTHE GRAVITY OF THE EARTH Filed April 2 Patented Dec. 13, 1921. i I1,652,255

UNITED STATES PATENT OFFICE.

WILHELM SCHWEYDAR, OI POTSDAK, GERMANY.

GBAVITATION METER FOR MEASURING THE VERTICAL GRADIENT 015 THE GRAVITY OFTHE EARTH.

Application filed April 9, 1927, Serial No. 182,442, and in'GermanyMarch 11, 1926.

This invention relates to a gravitation the counter-poise g that can besuspended meter, that is to say, to an apparatus for from the scale-beameither directly, or inmeasuring the vertical gradient of the gravdirectly by the intermediar of a comparaity of the earth by comparingthe bifilar tively long thread 1-, as in icated in dotted 5 turningmoment due to gravity with the torlines. In order to prevent thescale-beam sional moment of a helical spring. from being turned when theknob is turned,

With all known apparatus of this kind a checking device w is provided bymeans of the length of the helical spring is strongly which the beam canbe held fast in any deinfiuenced by changes of temperature so that siredposition.

10 the employment of such a spring is possible The poise c is providedwith a pointer m only in rooms that are particularly protected and thecasing a with a pointer 11. and the aras regards temperature. Theinvention obrangement is such that-the opposite ends of viates thisdrawback by substituting for the the two pointers lie in close proximitytoone sprin a wire, the upper end of which is caranother; a mirror p issuspended from the 16 ried y a scale-beam balance, for instance, pointerends by means of two threads 0. by a counter-poise. The influence of theThe manner of operation of the device is temperature is now much.smaller. The as follows: measurement is effected by suspending, theAfter the instrument has beenoset up and counter-poise first directlyfrom the scaleadjusted to accurately vertical position, the

20 beam and then indirectly, viz. by the inter knob e is turned so as todistort the wire d, position of a comparatively long thread. the axialturning of the wire being trans- The effect of the counter-poise isdifferent mitted to the poise c and the wires f being in the two casesbecause the gravity acts in crossed correspondingly until they havearboth cases by different strengths owing to rived at the lace ofunbalance, in the prox- 25 the distances of the counter-poise from theimity of which a measurable turnin of the earths centre being differentin the two pointer on about the distorted thread d is efcases, and thequantity to be measured can fected by a slight alteration of the pull ofbe ascertained by-that difference. the poise a. The lifting or sinkingof the The observation of the turning of the appoise g and of the thread(1, that is to say,

paratus can be effected by the reading of a the longitudinal shifting ofthese members, mirror. arising by said turning of the knob e, 18

The invention is illustrated dia ammaticompensated by a correspondinginclination cally and by way of example on t e aeoomof the scale-beam7c, the latter being free of panying drawing, on which I 36 Figure 1shows an apparatus provided vertical gradient of the gravity thecounterwith one main poise and one counter-poise, oise g is suspendedfirst directly from the and cam, as shown in full lines, and then 1n-Figure 2 shows a modification in which directly by the intermediary ofthe threadr, two main poises and two counter-poises are as shown indotted lines, and finally the dif- 40 used- I ference of the deflectionof the pointer m 15 011 the a ing, Fig. 1, en fl ascertained, ormeasured respectively, 1n a in which can be adjusted accuratelyvertiknown manner preferably by meansof the ca 1y by adjustin screws 6.The main poise mi ro c is carried chiefl y by the wire d and partly, Ith difi ati n, Fi 2, two 1nstru-.

45 i. e. for a very small part, by threads f, f ments .of theconstructura form shown m guided over rolls 9 and kept under a cer-'Fig. 1 are combined with each other. The tain tension by small poises h.Wh'en these characteristic difference being that the leftthreads areunder the pull of the poises h, hand pointer n is attached not to theeasthey are clamped fast in the respective posiing, but to the lefthandcounter-poise 0 tion b means of suitable clamping devices whereby atwice as large deflection of the (not s own) provided near therolls g.mirror p is obtained and the accuracy of The wire d is attached to oneend of the the reading is, therefore, doubled. scale-beam k thatoscillates on a horizontal I claim: I axle i; the wire (1 can bedistorted by a knob 1'. A gravitation meter for measuring the e. Theother end of the scale-beam carries vertical radient of the gravity orthe earth,

comprising, in combination, a scale-beam, a thread suspended from onearm of said beam, a poise suspended from said thread, means fordistorting the thread, two further threads connected with said poise andbeing so weighted as to partly balance the Weight of said poise, and acounterpoise suspended from'the other arm of the said scale-beam andbeing adapted to be suspended from the same in difierent heights.

2. A gravitation meter for measuring the vertical gradient of thegravity of the earth, comprising, in combinatlon, a scale-beam, a threadsuspended from one arm of said beam, apoise suspended from said thread,means for distorting the thread, two further threads connected with saidpoise and being so weighted as to partly balance the weight of saidpoise, a counter-poise suspended from the other arm of the saidscale-beam and being adapted to be suspended from the same in differentheights, and a reading.

mirror suspended in bifilar manner, one of the appertaining suspensionthreads extending from the said poise the other from a counter-point. V

3. A gravitation meter for measuring the vertical gradient of thegravity of the earth, comprising, in combination, a scale-beam, a threadsuspended from one arm of said beam, a poise suspended from said thread,means for distorting the thread, two further threads connected with saidpoise and being so weighted as to partly balance the weight of saidpoise, a counter-poise suspended from the other arm of the saidscale-beam and being adapted to be suspended from the same in differentheights and a checking device adapted to check the said beam in anydesired position.

In testimony whereof I. have aifixed my signature.

WILHELM SCHWEYDAR.

